Molasses and different plant-derived sugar-containing extracts, like beet juice, cane juice and starch hydrolysates, are used as raw material in a wide range of fermentation industries in producing alcohol, yeast, citric acid, glutamic acid, lysine and many other fermentation products. When the primary product has been recovered from the fermentation broth, a dilute by-product broth remains. When this dilute by-product from the fermentation is concentrated, it is generally called "vinasse". Other names are CMS (Condensed Molasses Solubles) and CPL (Complement Proteique Liquide). The traditional uses of vinasse have been its disposal as waste to the environment (often without concentration), its use as a potassium fertilizer, and its use as an additive in animal feed. Vinasse has been used as an additive in animal feed because it provides metabolizable energy at a low cost and also acts as a binder. The value of vinasse as a source of protein has also been examined (Deleplanque, G. & Maindron, G., 1982: Le C.P.L. et la Pulpe Surpressee Ensilee, Secopal S.A.).
Vinasse contains a high proportion of potassium, which may cause problems for example as disorders in the magnesium absorption in an animal fed on vinasse (Tomas, F. M. & Potter, B. J., 1976: The effect and site of action of potassium upon magnesium absorption in sheep, Aust. J. Agric. Res., 27, 873-880; Fontenot, J. P., Allen, V. G., Bunge, G. E., and Goff, J. P., 1989: Factors influencing magnesium absorption and metabolism in ruminants. Journal of American Science, 67, 3445-3455). Processes have been developed to reduce the high proportion of potassium (FR 1 497 480, Lesaffre & Cie., 1967; FR 2 573 088, Beghin-Say, S.A., 1986; NL 6 800 313, Julsingba, J., 1969; and DE 1 817 550, 1970). The processes are based on precipitating potassium as a salt or as a double salt in the presence of sulphate ions under essentially neutral conditions. Vinasse products with reduced potassium content are sold under the tradenames of Prouvital, Proteinal, Sirional, Viprotal, etc.
Environmental restrictions have limited the disposal of vinasse as a waste and consequently increased the supply of vinasse as an additive for animal feed and as a fertilizer. The demand for these two purposes is limited, and a serious oversupply situation thus exists on the market. Therefore there is an increased interest in recovering valuable components from vinasse.
For example betaine can be recovered through chromatographic separation methods. Betaine can also be recovered by utilizing ion exchangers, which may be either cationic or anionic. Other valuable components which can be recovered are glycerol, monosaccharides, amino acids and succinic acid.
After these valuable components have been recovered, a different kind of vinasse remains, the concentrations of the remaining components in the vinasse being higher than before. The potassium content of the product is very high, thus limiting its use in animal feed. On the other hand, the percentage of the organic compounds in the product is also high, thus limiting its use in fertilizer applications.